Synthesis and crystal structure of MgB12

被引：24

作者：

Adasch, Volker

Hess, Kai-Uwe

Ludwig, Thilo

Vojteer, Natascha

Hillebrecht, Harald

机构：

[1] Univ Freiburg, Inst Anorgan & Analyt Chem, D-79104 Freiburg, Germany

[2] DRONCO AG, D-95632 Wunsiedel, Germany

[3] Univ Munich, Inst Mineral Petrol & Geochem, D-80333 Munich, Germany

[4] Freiburger Mat Forschungszentrum, D-79104 Freiburg, Germany

来源：

JOURNAL OF SOLID STATE CHEMISTRY | 2006年 / 179卷 / 09期

关键词：

synthesis; single crystals; structure analysis; magnesium boride; boron rich boride; B-21; unit; WDX measurements;

D O I：

10.1016/j.jssc.2006.03.045

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

Single crystals of MgB12 were synthesized from the elements in a Mg/Cu melt at 1600 degrees C. MgB12 crystallizes orthorhombic in space group Puma with a = 16.632(3) A, b = 17.803(4) A and c = 10.396(2)A. The crystal structure (Z = 30, 5796 reflections, 510 variables, R-1(F) = 0.049, wR(2)(I) = 0.134) consists of a three dimensional net of B-12 icosahedra, and B-21 units in a ratio 2:1. The B-21 units are observed for the first time in a solid compound. Mg is on positions with partial occupation. The summation reveals the composition MgB12.35 or Mg0.97B12, respectively. This is in good agreement with the value of MgB11.25 as expected by electronic reasons to stabilize the boron polyhedra B-12(2-) and B-21(4-). (c) 2006 Elsevier Inc. All rights reserved.

引用

页码：2916 / 2926

页数：11

共 28 条

[1]

ADASCH V, 2005, THESIS U BAYREUTH GE

[2]

ADASCH V, IN RPESS J SOLID STA

[3] Synchrotron powder diffraction Rietveld refinement of MgB20 crystal structure [J].